Why DOMNodeList can be used with foreach (below) eventhough its an object ?

[jd2007]

<?php
    $xml = new DOMDocument();
   $xml->load("caldb_users.xml");
  $i=$xml->getElementsByTagName("db");

foreach ($i as $x)
{
echo $x;
}
?>

[PFMaBiSmAd]

From the php manual -

 

As of PHP 5, it is possible to iterate objects too.

 

Here is even more - http://www.php.net/manual/en/language.oop5.iterations.php

[jd2007]

thanks